1. Field of the Invention
The invention relates to a sampling device provided with a valve unit to be arranged at a conduit and a receiving unit arranged in a removable way for receiving a sample of a fluid flowing in the conduit, the valve unit being spring-biased in the closing direction, the receiving unit being equipped with a closure that is spring-biased in the closing direction, the valve unit being constructed to open towards the inside and the receiving unit to open towards the outside, and the receiving unit when arranged at the valve unit being effectively connected with the lock in a sealing way.
2. Description of the Prior Art
For various reasons (quality control, process monitoring, environmental protection, etc.), there are a growing number of instances where the removing of liquid or gaseous samples from conduits is required. The samples range from innocuous products such as water (e.g. reprocessing) and beverages to fuels and pure cold solvents and to all sorts of dangerous chemicals (hot acids, halogens, etc.).
Harmless substances may be tapped from the conduit by customary means such as by way of a faucet or a valve. However, the resulting dead space or the short dead-end conduit are very disadvantageous because a certain amount of the substance to be tapped needs to be poured away and/or more of the substance than the required amount needs to be tapped in order to obtain a significant sample. Besides, the dripping fluid requires subsequent rinsing and/or cleaning.
The more poisonous, dangerous and/or expensive a product, the more important becomes the problem of sampling. In devices for the removing of such liquid or gaseous samples from conduits, for example in installations of the chemical industry or the foodstuffs and beverages industry, it must guaranteed that samples are tapped from conduits and filled in receptacles in a way that neither the contents of the conduit nor the sample get into contact with the ambient air or with any alien matter such as precipitation or residues from an earlier sampling process, and that also after the removal of the receptacle no product will escape as gas into the environment or drip down in the form of a liquid.
From DE-3142875, GB-907495, U.S. Pat. No. 2041694, SU-363890 or FR-2067722 valve units of sampling devices are known which permit the removal of a sample from a conduit and the feeding of it to the connection piece for the connection of a receptacle. Such valve units without an assigned receptacle and with only one connection piece are not capable, on principle, of satisfying the requirements mentioned above.
From DE-929398, U.S. Pat. No. 3744319 and SU-549706 sampling devices are known which enable that a sample be removed from a conduit and that it be fed to a receiving unit. These sampling units possess dead spaces and thus do not satisfy the formulated requirements.
From U.S. Pat. No. 4150575 a sampling device is known which enable that a sample be removed from a conduit and that it be fed to a receptacle of a receiving unit provided with a piston. While this sampling device essentially guarantees that the contents of the conduit or of the sample do not get into contact with the ambient air, and that after the removal of the receiving unit no product will escape and get into the environment, this sampling device is actuated by the mounting or removing process of the receiving unit. The time of the sampling is determined by the actuation of a lock of the receiving unit on the valve body, that is the valve unit is opened during the fastening process of the receiving unit and closed when the tight connection is loosened. If the locking connection of the receiving unit is loosened, which is done manually at the neck of the receiving unit, the receiving unit is released immediately so that it must be held by hand. When handling dangerous products this procedure is inadmissible, work regulations and environmental protection require higher safety standards which are not guaranteed in this case. An actuation of the valve unit independent of the locking of the receiving unit is not provided in this sampling device nor is it possible.
From EP-0141940 a sampling device is known which enables that a sample be removed from a conduit and that it is fed to a receptacle of a receiving unit. This sampling device essentially guarantees that the contents of the conduit or the sample will not get into contact with the ambient air and that after the receiving unit has been removed no product will escape and be set off into the environment. However, the necessary safety is not guaranteed, because the valve unit may also be opened if no receiving unit is arranged at the valve unit. No measures are taken to avoid a possible discharge of products which can escape as gas into the environment or drip down as liquid after the receiving unit has been removed. In the case of this sampling device, an actuation of the valve unit depending on the presence and the locking of the receiving unit is not provided nor is it possible.